Flexible tubing



Nov, 28, 1.933.

I .RADQ

FLEXIBLE TUBING l Filed Feb. 10, 1930 Patented Nov. 28, 1933` l UNITED STATES PATENT orrlcEy rLExIBLEjrUBmG Leopold Rada, Berlin-Wannsee, Germany' 4 Application February 10, 1930, Serial No. 427,412,

. and in Germany September 9, 1929 3 Claims. (Cl. 13j-90) The invention relates to flexible tubing with of the flexible tubing, so that the inserted lining an inner lining and consists substantially in that possesses longitudinal folds. It is likewise preferthe materials which are used for the inner lining able to employ linings which in the extended conare known in themselves but have not been sugdition possess a greater length than the flexible 5 gested previously for this purpose. The matetubing, so that the inserted lining possesses transcc rials are non-fibrous cellulose foils or cellulose verse folds. Such a lining follows all the bending foils lined with metal foils, which are likewise and extending of the flexible tubing without already known. When employing these materials kinking. it is possible to use all kinds of flexible tubing of There are many ways of fixing the lining to the l rubber or rubberized materials as well as flexible inner wall of the flexible tubing. For example, metal tubing and the like for such liquids and the lining may be merely inserted loosely in the gases as would attack the bare material of the flexible tubing. the ends only being attached to tubing and would thus themselves be attacked the tubing. This type of attachment is particuor contaminated. This advantage applies particlarly suitable for very elastic rubber tubing. The l ularly in the case of tubing for motor spirit since lining may of course be attached to the rubber 7a such spirit has a solvent action on rubber. tubing by suitable adhesive along the whole of l By cellulose foils is understood the thin nonflits length. This attachment, however, is only brous celulose membrances, known to the trade suitable for stiff tubing or for such asl are not to be and usually made from viscose, for example, celluexcessively bent, for although the cellulose foil is lose hydrate foils, as well as similar products to a certain extent extensible, it has no elasticity, 75 which are manufactured in sheet form from the with the consequence that, in the CaSe 0f Sharp different cellulose derivatives (e. g cellulose bends, the'lining will kink. acetate). It has been found particularly advantageous By lining these cellulose foils with thin metal merely to attach as known the lining in isolated foils, e. g. aluminum foil, using suitable adhesives places to the inner surface of the flexible tubing, sa (e. g. paste, bone glue, gelatine solution, cellufor example by sticking them together in places. loid solution, colophonium solution, solution of According to a form of construction, the attachcaoutchouc or gutta-percha or solutions of natment to the inner surface of the flexible tubing ural or synthetic resins) thin but extremely resistis effected by means of annular retaining parts,

ant metal-cellulose foil is obtained in the known for example. metal rings, spiral springs or the 85 manner. like.

It is also known, by applicants copending ap- The flexible tubing according to the invention plication Serial Number 352,252 and U. S. Patmay be manufactured in a variety of ways. For ent Number 1,831,751 issued November l0, 1931, instance, the lining may be drawn in to the finthat hollow bodies can be manufactured of vstrips ished flexible tubing, that is to say both the 90 of these cellulose foils or metal-cellulose foils by tubing and the inner lining for it are manufacwinding several layers of the strips round a core, tured separately. It is also possible to manufacthe separate windings being glued together if ture the flexible tubing in such a manner that the necessary. This process for the manufacture of inner lining is rst wound on a mandrel and the hollow bodies as well as the hollow bodies themouter component of the tubing is then formed 95 selves can be employed with particular advanover the lining e. g. by winding. tage for the purpose of the present invention. In the case of flexible tubing in which the By employing these known materials for the inner lining is attached by means of annular lining of iiexible tubing, a flexible tubing is obretaining parts, for example, metal rings, spiral tained, in which according to the invention the springs or the like, the metal rings or spirals are 100 inner lining comprises a tubular insertion of first of all placed on a mandrel, the cellulose foil non-fibrous cellulose foil wound in a plurality of alone or cellulose foil in combination with metal layers. In this connection the cellulose foil may intended for the lining is then wound round the be combined by means of adhesives with a metal said rings or spirals, and over this is wound the foil. By using metalfoil, either alone or in comouter sheath consisting e. g. of rubber or rubber- 105 bination with cellulose foil, the impermeability of ized fabric and if necessary vulcanized under the liningis considerably increased and the cellupressure. On drawing out the mandrel from the lose foil is prevented from shrinking. flexible tubing after vulcanizing, the tubing so It has been found preferable to keep the diameobtained is corrugated in longitudinal section,

ter of the lining greater than the internal lining and has great flexibility on account of the corru- 110 gation of the lining of cellulose or metal-cellulose. This is especially the case, when the winding of the cellulose foil or of the metal-cellulose is effected without sticking the inlividual layers together. In this case, the lining is pressed into the corrugations and lield firmly by the metal rings or the spiral wire. In this form of construction, it is in no case necessary to stick the lining to the inner wall of the flexible tubing.

The use of linings for flexible tubing according to the invention has a particular advantage for metal flexible tubing, since the otherwise necessary packing of the spiral turns of the metal flexible tubing may be entirely omitted. This object is achieved in a very much greater measure by the provision of a lining according to the present invention.

When metal-cellulosefoils are used it is in many cases advantageous to use the metal foil as the innermost layer of the lining of the flexible tubing.

This formation of the inner lining is particularly advantageous in the case of tubes which are used for conveying rapidly evaporating fluids. The metal foil protects the cellulose hydrate foil from the detrimental action of these fluids, which cellulose hydrate foil would otherwise become brittle under the action of the vapors of the fluids. l

In the accompanying drawing:

Fig. 1 is a view partly in section and partly in elevation of one form of the invention.

Fig. 2 is a similar view of a modified form, and

Fig. 3 is a modification of still another` modifled form.

By way oi example, forms of construction of the invention are shown diagrammatically in the accompanying drawing, in which, Figure 1 shows a flexible rubber tubing l, provided with a lining 2 of cellulose foil or metal-cellulose foil. In Figure 2 the lining/ 2, which is longer than the flexible tubing itself, is.introduced into the tubing in such a manner as to produce transverse folds. 'I'hese folds are stuck at the places marked 3 to the inner wall of the tubing. Figure 3 shows a flexible tubing manufactured in the manner hereinbefore described by winding on a mandrel. A spiral spring 4 is first placed on the mandrel, and on this the lining 2 oi' cellulose foil or metal-cellulose foil is wound in the known manner, without sticking the layers together. The flexible tubing is now manufactured over the wound lining in the known. manner e. g. by winding rubber sheets having a fabric lining, and vulcanized. Such a flexible tubing possesses great flexibility although the inner lining of cellulose fllm possesses of itself almost no elasticity. By reason of the corrugated folding, however, the lining is able to follow the movements of the flexible tubing owing to the extension of the folds, without kinking or bending.

The lining of rubber tubing with spirallywound, so-called flexible metal tubing is known. as is also the use of asbestos linings or the like, for packing the said spirals. Apart from the fact that rubber tubing provided with metal linings in this way is'excessively heavy, there is the additional disadvantage that, despite careful packing of the turns of the spiral. it is impossible to avoid the liquid in time flnding its way to the wall of the tubing and attacking it.

What I claim is:

1. A ilexible tubing comprising a casing of flexible material and a lining therefor consisting of helically wound cellulose film coated with metal foil constituting in the lining a plurality of separated layers.

2. A flexible tubing comprising a casing of flexible material and a lining therefor consisting of helically wound cellulose film coated with metal foil constituting in the lining a plurality of l separated layers, said lining being annularly corrugated topermit longitudinal extension of the lining incident to the bending of the flexible casing. l

3. A flexible tubing comprising a casing of flexible material and a lining therefor consisting of helically wound cellulose film coated with metal foil constituting in the lining a plurality of separated layers, said lining being annularly corrugated to permit longitudinal extension of the lining incident to the bending of the flexible casing, and adhesive' material applied at segregated spots to connect the lining with the casing to prevent displacement lof the lining as a whole within the casing.

' LEOPOLD RADO. 

